1. Field of the Invention
The present invention relates to a digital rights management, and particularly, to a method for managing digital rights in a broadcast/multicast service of a mobile communications terminal.
2. Background of the Related Art
In general, a broadcast/multicast service refers to a service for providing a mobile communications terminal with over-the-air broadcasting or various additional information, or the like. The broadcast/multicast service is a new type of service which includes a broadcast service in which a provider provides useful information to all clients who subscribe to its service, and a multicast service for providing information only to a particular group of clients who have previously subscribed to a particular subject or content.
As the broadcast/multicast service can provide the same information simultaneously to multiple clients, efficient management of network resources allows a high bandwidth application to be provided. Also, since the broadcast/multicast service provides various types of high speed services according to a client's request, the increasing demands and requirements of the clients can be satisfied.
In order to safely protect and systematically manage rights with respect to contents provided by the broadcast/multicast service, service protection and content protection functions are required. Digital rights management (DRM), which is recently being actively discussed, is applied to the broadcast/multicast service to allow protection of the contents provided by the broadcast/multicast service.
The DRM can previously intercept an unauthorized (or illegal) use of contents by converting the contents into a package-type encrypted data using an encryption technique, and thereafter permitting users who have completed an authentication and confirmation procedure for authorization to gain access to the original contents.
Hence, in the method for managing digital rights of the related art broadcast/multicast service, each terminal using the service receives a rights object (RO) for using the service from a rights issuing server (Rights Issuer: RI), and thereafter uses the received RO to decode an encrypted service data or content. Here, the RO may be encrypted by using a public key of each terminal.
That is, the RI should transmit the RO that is encrypted by using the public key of each terminal, to the terminals that use the broadcast/multicast service. For example, if a K number of terminals use the broadcast/multicast service, the RI generates the ROs, each of which is encrypted by using the public key of each of the K number of terminals, and must repeatedly transmit the generated ROs to all the terminals.
However, in the method for managing the digital rights in the broadcast/multicast service, if there are many terminals using the service, the RI must generate/manage the ROs encrypted using the public keys of each terminal one by one, which results in an increased operation load as well as an inefficient network operation and management.